Over Voltage?

not overvoltage at all
Your mains voltage is sagging when a high start current (motor) energizes. Could be a degraded connection on the incoming line or it's just too small mains conductor somewhere along the line.
A line conditioner wouldn't take care of this unless it's an active - regenerative type then it could. But better to locate & fix the actual problem. You might need an electrician unless you're adept...

Put your system on the other leg of your panel. Most furnaces are 120 volt so that should not be a problem.

By the way what kind of heat do you have. Oil or gas, Boiler or furnace, electric resistance or heatpump? It is a brown out condition not over voltage as Bob pointed out

Thanks for your help and sorry fo the delay, Ive been out of town at a hockey tournament in WI.
I've got GFA. It did help to shut off my power amp that I use for garage speekers not used fo winter months in the Chicago area. I typically leave this amp on all the time. I'll look into the degraded connection. My furnace breaker is on the other side of the pannel. Equipment is located near the furnace but not too close.

Are you sure it is on the other side.
Panels are usually wired like this except for some old panals like push a matics panels.

1 2
3 4
5 6
7 8
and so on

Line 1 or leg 1 is 145&8
Line 2 or leg 2 is 236&7

This is setup this way so when you put in a 2 pole breaker you get 208-230 volts AC.

Just because the furnace is on the right side & your TV is on the left does not mean they are on differant lines.
I do not know how much you know of electrical panels.

Take a look at this thread.
Is talks alot about Electrical.

On one leg or two legs?

Take a look at this thread.
Is talks alot about Electrical.

On one leg or two legs?

It is in Tech Talk Forum.

Thanks, I dont know much about electrical pannels. I'd like to approach the trial and error before calling an electrician. I wont be pulling apart the pannel or anything. I can change a light switch, or a socket or a breaker but I wount mess with the pannel. It appears shutting off the amp helped. Problem is, in the summer I'll keep that amp on all the time so I'd like to fix the problem. I'll check the guage of the wire and see if I can put a 20amp in there as its currently 15. It just seems that with my tv shutting off and on again that it cant be good for it besides it being annoying. I dont know off hand if the equipment breaker is directly accross from the furnace breaker.